Severe Thunderstorm Warning 221, NWS Jackson, MS

Area Forecast Discussion
National Weather Service Jackson MS
126 PM CDT Sat May 23 2020

.UPDATE...
Updated for 18Z aviation discussion

&&

.AVIATION...
18Z TAF discussion:
VFR ceilings are occurring at TAF sites outside of thunderstorms.
Where a thunderstorm occurs, brief lowered ceilings and vis can be
expected through the rest of the afternoon. Convection will
diminish with loss of daytime heating this evening. Some brief
MVFR ceilings could occur around daybreak tomorrow morning but
otherwise VFR conditions will occur tomorrow outside of additional
storms that develop. /28/

&&

.DISCUSSION...
As expected, a decaying MCS is moving across northeast Louisiana
with some outflow boundary having made it into the Delta region of
Mississippi. This has also brought a few storms to that region as
well this morning. Expect that as the remnant outflow boundary
lingers in the region, additional showers and storms will develop
during the afternoon as daytime heating peaks. Morning microburst
analysis is not overly different than yesterday. PW values across
the region are a little higher around 1.45 inches per 12Z KJAN
sounding. Vertical totalsand mid level lapse rates are good and
supportive of at least some strong storms today. It won't be out
of the question for additional severe storms as well. Coverage
should be greater today than yesterday with the highest
concentration being along and southeast of the Natchez Trace
corridor, at least per hi-res CAM guidance. Otherwise,
temperatures will be warm and very summerlike once again today.
Highs will be in the lower 90s again today with dewpoints in the
upper 60s to lower 70s. /28/

Prior discussion below:

Today: This morning GOES-East water vapor & infrared imagery
indicate a large MCS/decaying complex of thunderstorms ongoing
across eastern Oklahoma & across Arkansas. This MCS is gradually
losing steam as is propagates southeast into the ArkLaTex &
towards the region. This is in response to a shortwave trough
digging through the central Plains to the Ozarks. Synoptic &
surface analysis indicate subtle troughing extending into the Gulf
of Mexico while a surface warm front is draped across the
ArkLaTex-north Mississippi. Expect any decaying storms to make it
just in our far northwest Delta or remnant outflow boundary to
drift slowly move in. Local CAM guidance indicate this solution
will pan out but with some convection closing in a little further
east, it might be able to sneak in this morning before sunrise.
Otherwise, expect a near carbon copy of yesterday. The region will
remain under the influence of return flow on the western
periphery of 700-850mb thermal ridge over the Florida Peninsula &
just off the southeast Atlantic coastline. Expect a more
summertime pattern with return flow of high Theta E laden air of
nearly 330K+ @ 850mb Theta E & PWs potentially approaching an inch
& a half to an inch & three quarters. This will help any light
showers to develop by mid-morning along & southeast of the
Natchez Trace & scattered rain & storm chances spread northwest
over a majority of the region, outside of the ArkLaMiss Delta.
Similar to yesterday, with above normal heat & humidity (i.e.
highs in low 90s & heat indices peaking in mid 90s) will combine
with 6.5-7.5 deg 700-500mb lapse rates/27-29 deg. C. vertical
totals & subtle south-southwest 0-2km bulk shear ~10-15kts. This
supports some strong & isolated severe microburst potential, with
gusty winds/marginal hail, especially in any north-northeast
propagating segments. However, HRRR is decreases confidence on
coverage due to some PWs less than an inch & a half. Due to that &
being so mesoscale driven, there remains uncertainty of exact
coverage of scattered diurnal development. Thus, not enough
confidence to introduce any mention in the HWO.

Tonight: Expect these storms to gradually wind down at most few
hours after sunset & especially before midnight. For tonight, low-
mid-level ridge will remain parked to our east. Persistent southerly
flow will keep partly cloudy skies & muggy & above normal warmth
around in the upper 60s in the east to low 70s west of Interstate
55. /DC/

Sunday through next Friday night: a rather wet, early summer like
weather pattern will maintain warm and humid conditions for the
ArkLaMiss through the long term. There is consensus among the NWP
guidance in depicting an upper low closing and cutting off over
the Southern Plains region and persisting through next week. As
this happens, the forecast area will experience prolonged
southerly flow that would support considerable coverage of mostly
diurnal convective precipitation, with coverage most pronounced
over western/central portions of the ArkLaMiss.

Increasingly cyclonic and convergent flow will support fairly
steep mid level lapse rates that could support a few strong/severe
storms, although the southerly low level flow will hasten daily
convective development and this could limit heating/destabilization.
As we go later into the week, the upper low will likely weaken
and retrograde some resulting in slightly warmer mid level
temperatures. In any case, with precipitable water exceeding two
inches at times, locally heavy rainfall could become a concern,
especially in the Tue-Thu time frame when moisture convergence
should be most persistent. /EC/

&&

.PRELIMINARY POINT TEMPS/POPS...
Jackson       91  69  90  69 /  45  24  26  13
Meridian      91  67  91  67 /  45  23  34  15
Vicksburg     90  72  90  70 /  45  19  28  12
Hattiesburg   90  69  89  68 /  45  11  37  16
Natchez       89  70  88  69 /  45  24  37  11
Greenville    91  72  89  71 /  30  19  23  18
Greenwood     91  71  91  69 /  28  22  22  21

&&

.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.

&&

28

Hazardous Weather Outlook
National Weather Service Jackson MS
417 AM CDT Sat May 23 2020

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
240930-
Ashley-Chicot-Morehouse-West Carroll-East Carroll-Richland-
Madison LA-Franklin LA-Catahoula-Tensas-Concordia-Bolivar-
Sunflower-Leflore-Grenada-Carroll-Montgomery-Webster-Clay-Lowndes-
Choctaw-Oktibbeha-Washington-Humphreys-Holmes-Attala-Winston-
Noxubee-Issaquena-Sharkey-Yazoo-Madison MS-Leake-Neshoba-Kemper-
Warren-Hinds-Rankin-Scott-Newton-Lauderdale-Claiborne-Copiah-
Simpson-Smith-Jasper-Clarke-Jefferson-Adams-Franklin MS-Lincoln-
Lawrence-Jefferson Davis-Covington-Jones-Marion-Lamar-Forrest-
417 AM CDT Sat May 23 2020

This hazardous weather outlook is for portions of southeast
Arkansas, northeast Louisiana, central Mississippi, north central
Mississippi, and south central Mississippi.

.DAY ONE...Today and Tonight

The probability for widespread hazardous weather is low.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

The probability for widespread hazardous weather is low.

.SPOTTER CALL TO ACTION STATEMENT...
The activation of storm spotters, HAM radio operators, and
emergency management personnel in support of severe weather
operations is not expected through next Friday.

23

&&

...HAZARD LEGEND...

No short term hazards expected.

...USEFUL WEATHER WEB PAGES (URLS)...

NWS JAN Home page...
   https://www.weather.gov/jan
Stay Aware, Stay Safe NWS JAN Briefing Page...
   https://www.weather.gov/jan/safe
Latest Weather Briefing...
   https://www.weather.gov/jan/weather_briefing

Find NWS JAN on Facebook...
   https://www.facebook.com/NWSJacksonMS
Follow NWS JAN on Twitter...
   @NWSJacksonMS
Follow NWS JAN on Youtube...
   https://www.youtube.com/user/NWSJacksonMiss

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>